Internal chemical system for decelerator



F. BLOETSCHER ET AL 3,59,225

INTERNAL CHEMICAL SYSTEM FOR DECELERATOR July 7, i970 2 Sheets-Sheet l Filed May 27, 1968 jid? 7 w'i0 F. BLoETscHER ET AL 3,59,22

NTERNAL CHEMICAL SYSTEM FOR DECELERATOR 2 ShectS-Shect 2 Filed May 27, 1968 United States Patent O 3,519,225 INTERNAL CHEMCAL SYSTEM FOR DECELERATOR Frederick Bloetscher, Cuyahoga Falls, and Fred R.

Nebiker, Akron, Ohio, assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Air Force Filed May 27, 1968, Ser. No. 732,228 Int. Cl. B641) 1/58; B64d 17/80 U5. Cl. 244-32 6 Claims ABSTRACT OF THE DISCLOSURE Two bladders filled with Wood alcohol and water have their necks projecting through holes in a fabric holder which is attached at opposite ends to the forward and rearward end of a decelerator. Cords are tied around the necks of the bladders and attached to the ends of the fabric holder so that the necks are ruptured when the fabric holders are pulled apart during decelerator deployment. Due to heat, the wood alcohol and water vaporize and partially inflate and cool the decelerator.

The present invention pertains to deployable aerodynamic decelerators and more particularly to an internal chemical system for use in such decelerators. A deployable aerodynamic decelerator is a device which is stored in a highly compressed-folded shape and deployed into the airstream of a missile or other aircraft where it is normally inflated to its nal shape. The size and shape of the device result in an aerodynamic drag force which is applied to the aircraft or missile payload for stabilization and deceleration.

At high Mach numbers the heating environment can destroy the decelerators structure unless it is protected or cooled. Also, at high altitudes the decelerator often does not open. due to the lower density atmosphere resulting in a condition known as ag waving. A solution to the above two problems is obtained by using an internal chemical system to partially inflate the decelerator and to absorb heat during the decelerator deployment and system deceleration.

The chemical system uses a mixture of wood alcohol and water which vaporizes during the decelerator deployment thereby expanding to partially inate the derelerator and absorb heat during its expansion into a gas. Before deployment the fluid mixture is contained in two latex bladders used as redundant containers. The bladders are held in a fabric holder which is composed of two halves laced together at its midpoint. Web handles are sewn at opposite ends of the holder and there are holes in the holder at each end near the handles through which the necks of the bladders project. Two cords are tied around the neck of each bladder with one of the cords tied to the handle adjacent the hole through which the corresponding bladder neck projects and the other cord tied to the handle at the opposite end of the cylinder. A lanyard is attached from one of the handles to the forward end of the decelerator and a cord is attached from the other handle to the rear of the decelerator or to a deployment bag. As the decelerator is stretched during deployment the lacing of the cloth holder is broken pulling the holder into forward and rearward halves, thereby breaking the necks of the bladders and dispersing the fluid mixture. The heating environment due to the speed of the craft causes the fluid mixture to expand and vaporize thus partially inflating the decelerator and absorbing heat which cools the decelerator structure.

A decelerator in which the chemical system is preferably employed s a ballute which has the shape of a 3,519,225 Patented July 7, 1970 prolate spheroid with air scoops spaced around its outer periphery for inflation. The chemical system is attached to the interior of the ballute between the front and rear ends. The ballute with internal chemical system is completely deflated and stored in a compressed folded state in a deployment bag which is itself placed in a container that is attached to a missile or other aircraft. In use the container is thrust from the aircraft as is known in the art thereby deploying hte ballute. The chemical system partially inates the ballute and cools the structure. At this point air is rammed through the air scoops by the movement of the ballute to complete the ination.

Therefore the objects of this invention are to provide an internal chemical system for inating and cooling a decelerator, to provide a chemical system which absorbs heat during its expansion into a gas during decelerator deployment, to provide a chemical system for partially inflating a ballute and to provide a system for increasing the performance capability of deployable aerodynamic decelerators while maintaining light weight and flexibility.

These and other objects and advantages of the present invention will be more readily apparent from a consideration of the following detailed description of the dra-wings illustrating a preferred embodiment of the invention.

ln the drawings:

FIG. 1 is a diagrammatic View showing the parts of the chemical system as secured before deployment with certain redundant parts omitted for clarity;

FIG. 2 is a diagrammatic view showing the Chemical system within the ballute;

FIG. 3 is a diagrammatic View showing a missile in flight with all components of the decelerator packaged in the container;

FIG. 4 is a diagrammatic view showing the container separated from the missile and the deployment bag accelerated by its bridle to the container;

FIG. 5 is a diagrammatic view showing the ballute out of the deployment bag at which point the chemical system is operating; and

FIG. 6 is a diagrammatic view showing the ballute inated and separated from the deployment bag and container.

Referring now to FIG. 1 an internal chemical system 1 is shown having two bladders 2, 3 filled with a fluid which expands and absorbs heat such as by evaporation. One suitable combination is a mixture of wood alcohol and water. The bladders are held in a exible holder 4 composed of two halves 5, 6 laced together as shown at 7. This holder may conveniently be made of fabric. It is to be understood that the bladders 2, 3 may be filled with other type fluids and that holder 4 may be of other material than fabric and have other construction than being of two separable halves. Web handles 10, 11 are sewn on opposite ends of holder 4. Each half 5, 6 of holder 4 has a hole 15, 16 near its respective handle 10, 11 through which the necks 17, 18 of bladders 2, 3 project. One of the two cords 19 is tied at one end around neck 1.7 of bladder 2 and at the other end to handle 11 while the other of the two cords 19 is tied at one end around neck 18 and at the other end to handle 10. A shorter cord 20 is tied at one of its ends around neck 17 and at the other end to handle 10. A second shorter cord 21 is tied around neck 18 and to handle 11,

As shown in FIG. 2 the chemical system 1 is attached within decelerator 22. Lanyard 23 is attached at one end to the forward part of decelerator 22 and at the other end is tied to handle 10. Cord 24 is tied at one end to handle 11 and at the other end extended through the rear of decelerator 22 for attachment to a deployment bag.

As is evident from FIGS. 1 and 2, the chemical system 1 is operated by a force extending longitudinally outward along lanyard 23 and cord 24. This force causes the lacing 7 to break and to pull the holder 4 into two halves. It then places stress on the cards around the necks 17, 18 of bladders 2, 3 causing them to break thereby dispersing the fluid mixture.

Operation of the system as used in a ballute and with a missile payload will now be explained in conjunction with the sequence shown in FIGS. 3 to 6.

Referring now to FIG. 3, a missile 31 is shown in flight having a decelerator packaged in a cylindrical container 33 in its aft end. The decelerator is stored in a compressed folded shape in deployment bag 34 which is attached at one end to the interior of container 33 by a bridle 35 and laced 36 at the other end. Riser lines 37 connect the decelerator to the missile 31 and have attached thereto a knife (not shown) which is intertwined with lacing 36 so as to cut the deployment bag lacing 36 upon the riser lines 37 being extended.

The deployment sequence of the decelerator will now be explained with reference to FIGS. 4 to 6. As the container 33 is thrust from the missile 31 the deployment bag 34 is rapidly accelerated by its bridle 35 attached to container 33. The riser lines 37 are then pulled taut and upon being extended the knife (not shown) cuts the lacing 36 whereupon the ballute 39 is pulled from the opened deployment bag 34. At this point partial ination of the decelerator is caused by the vaporization of the liquids of the internal chemical system which have been released in ballute 39 due to the rupturing of the necks of the bladders. The ballute 39 is then fully inflated to a prolate spheroid by means of air scoops 41 which open into ballute 39. Apex cord 24 breaks separating the container 33 and deployment bag 34 from ballute 39.

In addition to the cooling method above described it is contemplated that the outer structure of the decelerator have a flexible ablating coating which reduces the heat absorbed by the decelerators structure and decreases the porosity of the fabric of the decelerator for proper ination. The combination of the internal chemical system and the exible ablating coating allows for a higher performance with a much reduced structural weight than a normal unprotected decelerator structure.

It is to be understood that various modifications may be evident that will fall within the scope of the invention. For example, only one bladder could be used in which case the holder could be eliminated. The bladder could have its neck secured to lanyard 23 and apex cord 24. Also, the bladder could be secured directly to the Wall or form part of the wall of the decelerator and have its neck secured to a cord attached to an opposite wall or through the wall to a deployment bag. Therefore, we intend to be limited only by a broad interpretation of the appended claims.

We claim:

1. The combination of; a decelerator, a bladder located within the decelerator, said bladder being secured within said decelerator and containing a vaporizable fluid, said bladder having a neck and secured within said decelerator by means of a lanyard attached at one end to the neck of said bladder and at the other end to a wall of said decelerator, whereby upon the decelerator being deployed the bladder is ruptured and the uid therein is dispersed within said decelerator.

2. The combination of: a decelerator shaped like a prolate spheroid and having air scoops around its periphery, a bladder located within said decelerator, said bladder being secured within said decelerator and containing a vaporizable fluid, and means whereby upon the decelerator being deployed the bladder is ruptured and the iluid therein is dispersed Within said decelerator.

3. The combination of: a decelerator, a deployment bag located outside the decelerator, a first bladder located within said decelerator and containing a vaporizable fluid, a second bladder located within said decelerator and containing a vaporizable lluid, a holder located within said decelerator and holding said bladders, said holder having handles at opposite ends and holes adjacent said handles, said bladders having necks which project through said holes, two cords for each neck, said cords being tied at one of their ends to the neck, one of said cords having its other end secured to a handle and the other cord having its other end secured to the other handle, a lanyard secured from one of the handles to the forward part of the decelerator and a cord secured from the other handle extending through the rear of the decelerator and attached to the deployment bag, whereby upon the decelerator being deployed the bladder is ruptured and the fluid therein is dispersed within said decelerator.

4. The combination according to claim 3 wherein said decelerator is shaped like a prolate spheroid having air scoops around its periphery and including a flexible heat protected coating on the exterior of said decelerator.

5. A combination of: a decelerator, a bladder located Within said decelerator, said bladder being secured within said decelerator and containing a vaporizable duid composed of wood alcohol and water, and means whereby upon the decelerator being deployed the bladder is ruptured and the iluid therein is dispersed within said decelerator.

6. The combination of a decelerator, first and second bladders located within said decelerator and containing vaporizable uid, a holder located within said decelerator and holding said bladders, said holder having handles at opposite ends and holes adjacent said handles, said bladders having necks which project through said holes, two cords for each neck, said cords tied at one of their ends to the neck, one of said cords having its other end secured to a handle and the other cord having its other end secured to the other handle, a lanyard secured from one of the handles to the forward part of the decelerator and a cord secured from the other handle to the rearward part of the decelerator whereby upon the decelerator being deployed the bladder is ruptured and the lluid therein is dispersed within said decelerator.

References Cited UNITED STATES PATENTS 11/1966 Kendall 244138 X 7/1968 Wykes 244-113 U.S. Cl. X.R. 244-113, 138 

